From b03b99a329a14b7302f37c3ea6da3848db41c8c5 Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams@intel.com>
Date: Mon, 27 Mar 2017 21:53:38 -0700
Subject: [PATCH] acpi, nfit, libnvdimm: fix interleave set cookie calculation
(64-bit comparison)
While reviewing the -stable patch for commit 86ef58a4e35e "nfit,
libnvdimm: fix interleave set cookie calculation" Ben noted:
"This is returning an int, thus it's effectively doing a 32-bit
comparison and not the 64-bit comparison you say is needed."
Update the compare operation to be immune to this integer demotion problem.
Cc: <stable@vger.kernel.org>
Cc: Nicholas Moulin <nicholas.w.moulin@linux.intel.com>
Fixes: 86ef58a4e35e ("nfit, libnvdimm: fix interleave set cookie calculation")
Reported-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
drivers/acpi/nfit/core.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 662036bdc65e..c8ea9d698cd0 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -1617,7 +1617,11 @@ static int cmp_map(const void *m0, const void *m1)
const struct nfit_set_info_map *map0 = m0;
const struct nfit_set_info_map *map1 = m1;
- return map0->region_offset - map1->region_offset;
+ if (map0->region_offset < map1->region_offset)
+ return -1;
+ else if (map0->region_offset > map1->region_offset)
+ return 1;
+ return 0;
}
/* Retrieve the nth entry referencing this spa */
--
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